Aircraft propulsion system with intermittent combustion engine(s)

Abstract

An aircraft system is provided that includes a first propulsor rotor, a first transmission, a second propulsor rotor, a second transmission and an intermittent combustion engine. The first propulsor rotor is rotatable about a first propulsor axis. The first transmission is coupled to the first propulsor rotor. The second propulsor rotor is rotatable about a second propulsor axis. The second transmission is coupled to the second propulsor rotor. The intermittent combustion engine is configured to drive rotation of the first propulsor rotor through the first transmission. The intermittent combustion engine is configured to drive rotation of the second propulsor rotor through the second transmission.

What is claimed is: 
     
       1. An aircraft system, comprising:
 a first propulsor rotor rotatable about a first propulsor axis; 
 a first transmission coupled to the first propulsor rotor; 
 a second propulsor rotor rotatable about a second propulsor axis; 
 a second transmission coupled to the second propulsor rotor, the second transmission different from and independent of the first transmission; and 
 an intermittent combustion engine configured to drive rotation of the first propulsor rotor through the first transmission, and the intermittent combustion engine configured to drive rotation of the second propulsor rotor through the second transmission independent of the rotation of the first propulsor rotor, 
 wherein the first transmission and the second transmission are configured to facilitate rotation of the first propulsor rotor and the second propulsor rotor at different rotational speeds during at least one mode of operation. 
 
     
     
       2. The aircraft system of  claim 1 , further comprising:
 a third propulsor rotor downstream of the first propulsor rotor and rotatable about the first propulsor axis; the intermittent combustion engine further configured to drive rotation of the third propulsor rotor through the first transmission. 
 
     
     
       3. The aircraft system of  claim 2 , further comprising:
 a first propulsor ring gear rotatable with the first propulsor rotor; 
 a third propulsor ring gear rotatable with the third propulsor rotor; and 
 a pinion gear rotatably driven by the intermittent combustion engine through the first transmission, the pinion gear meshed with the first propulsor ring gear and the third propulsor ring gear. 
 
     
     
       4. The aircraft system of  claim 2 , further comprising:
 a first propulsor ring gear rotatable with the first propulsor rotor; 
 a third propulsor ring gear rotatable with the third propulsor rotor; 
 a first pinion gear rotatably driven by the intermittent combustion engine through the first transmission, the first pinion gear meshed with the first propulsor ring gear; and 
 a second pinion gear rotatably driven by the intermittent combustion engine through the first transmission, the second pinion gear meshed with the third propulsor ring gear. 
 
     
     
       5. The aircraft system of  claim 2 , further comprising:
 a drivetrain coupling the intermittent combustion engine to the first propulsor rotor and the third propulsor rotor; 
 the drivetrain configured to rotate the first propulsor rotor and the third propulsor rotor in opposite directions; and 
 the drivetrain comprising the first transmission. 
 
     
     
       6. The aircraft system of  claim 1 , further comprising:
 a first drive structure coupling the first transmission to the first propulsor rotor; and 
 a first coupling connecting the first drive structure to the first propulsor rotor, the first coupling including a first propulsor ring gear and a first pinion gear, the first propulsor ring gear rotatable with the first propulsor rotor, and the first pinion gear rotatable with the first drive structure and meshed with the first ring gear. 
 
     
     
       7. The aircraft system of  claim 6 , wherein the first drive structure is configured as a driveshaft. 
     
     
       8. The aircraft system of  claim 1 , further comprising:
 an aircraft fuselage housing the intermittent combustion engine, the first transmission and the second transmission; 
 the first propulsor rotor and the second propulsor rotor located outside of the aircraft fuselage. 
 
     
     
       9. The aircraft system of  claim 8 , further comprising:
 an inlet configured to direct boundary layer air flowing along the aircraft fuselage to the intermittent combustion engine; and 
 an exhaust located at an aft end of the aircraft fuselage, the exhaust configured to direct combustion products generated by the intermittent combustion engine out of the aircraft system. 
 
     
     
       10. The aircraft system of  claim 1 , wherein, during at least a second mode of operation, the first transmission and the second transmission are configured to facilitate rotation of the first propulsor rotor and the second propulsor rotor at a common rotational speed. 
     
     
       11. The aircraft system of  claim 1 , wherein
 the first propulsor rotor comprises a first ducted rotor; and 
 the second propulsor rotor comprises a second ducted rotor. 
 
     
     
       12. The aircraft system of  claim 1 , wherein
 the first propulsor rotor comprises a first open rotor; and 
 the second propulsor rotor comprises a second open rotor. 
 
     
     
       13. The aircraft system of  claim 1 , wherein
 the first propulsor axis is laterally spaced from the second propulsor axis; and 
 the intermittent combustion engine is located laterally between the first propulsor axis and the second propulsor axis. 
 
     
     
       14. The aircraft system of  claim 1 , wherein the first transmission comprises a variable speed transmission. 
     
     
       15. The aircraft system of  claim 1 , wherein the intermittent combustion engine comprises one of a rotary engine, a piston engine, a rotating detonation engine or a pulse detonation engine. 
     
     
       16. The aircraft system of  claim 1 , wherein the intermittent combustion engine comprises a turbo-compounded intermittent combustion engine or a turbocharged intermittent combustion engine. 
     
     
       17. An aircraft system, comprising:
 a first propulsor including a plurality of first propulsor rotors rotatable about a first propulsor axis; 
 a first transmission coupled to the plurality of first propulsor rotors; 
 a second propulsor including a plurality of second propulsor rotors rotatable about a second propulsor axis; 
 a second transmission coupled to the plurality of second propulsor rotors, the second transmission different from and independent of the first transmission; 
 a powerplant comprising an intermittent combustion engine configured to drive rotation of the plurality of first propulsor rotors through the first transmission, and the intermittent combustion engine configured to drive rotation of the plurality of second propulsor rotors through the second transmission, 
 wherein: 
 at least one propulsor rotor from among the plurality of first propulsor rotors rotates in an opposite direction than a remainder of the plurality of first propulsor rotors, 
 at least one propulsor rotor from among the plurality of second propulsor rotors rotates in an opposite direction than a remainder of the plurality of second propulsor rotors, 
 the aircraft system is configured such that a mechanical power output by the powerplant is transferred to the first propulsor through the first transmission independent of the second transmission, and 
 the first transmission and the second transmission are configured to facilitate rotation of the plurality of first propulsor rotors and the plurality of second propulsor rotors at different rotational speeds during at least one mode of operation. 
 
     
     
       18. The aircraft system of  claim 17 , wherein
 the first transmission is configured as a first variable speed transmission; and 
 the second transmission is configured as a second variable speed transmission. 
 
     
     
       19. An aircraft system, comprising:
 an aircraft fuselage; 
 a first propulsor outside of and next to the aircraft fuselage, the first propulsor comprising a ducted propulsor rotor; 
 a second propulsor outside of and next to the aircraft fuselage, the second propulsor comprising a ducted propulsor rotor; 
 a first transmission housed within the aircraft fuselage, the first transmission coupled to the first propulsor; 
 a second transmission housed within the aircraft fuselage, the second transmission coupled to the second propulsor, the second transmission different from and independent of the first transmission; and 
 a turbo-compounded intermittent combustion engine housed within the aircraft fuselage, the turbo-compounded intermittent combustion engine configured to drive rotation of the first ducted propulsor rotor through the first transmission, and the turbo-compounded intermittent combustion engine configured to drive rotation of the second ducted propulsor rotor through the second transmission.